1. Technical Field
The present invention relates to a leader cloth for pulling a new belt into a paper machine and laying the leader cloth onto rolls when replacing a cloth or belt (referred to as a belt hereinafter) for the paper machine.
2. Background Art
In a paper machine for making paper, a belt which has extremely large width, length and weight, is laid onto the rolls, and processes such as squeezing water, conveying, drying are carried out on wet paper while the belt travels on the rolls.
When the belt functions have remarkably degraded, the belt is replaced with a new belt. In doing so, the following are required: the machine has to be stopped; the used belt has to be removed; and then, a new belt has to be laid therein. Since the belt is large in size and heavy, in order to carry out the replacing work safely and effectively, the following method has been conventionally employed. A used endless belt (referred to as old belt hereinafter) installed on the rolls is cut off in the width direction first. Then, the rear end of the old belt is joined to the front end portion of a new belt. The old belt is driven to travel in the front end portion direction to pull the new belt into the paper machine. After the new belt is laid onto the entire rolls, both ends of the belt are sewed together to form an endless belt on the rolls. However, in the above method, it is hard to remove the belt. The damaged used belt may be occasionally broken off while replacing the same with a new belt, and it takes a lot of trouble to gradually remove the leading used belt out of the paper machine while pulling the new belt into the paper machine. Therefore, now, after removing the old belt, a rope is laid onto the rolls in the paper machine, a new belt is connected to the rope, and the new belt is pulled onto the rolls in the paper machine by pulling the rope.
To guide the new belt onto the rolls smoothly and precisely as described above, the following method has been employed. A fabric called leader cloth is connected to the rear end portion of the rope. The leader cloth is connected to the end portion of the new belt, and the tensile force by traction via the rope is transmitted to the new belt via the leader cloth to pull the same onto the rolls.
To achieve the above object, leader clothes with various configurations and structures have been proposed. For example, the followings are known. In U.S. Pat. No. 5,306,393 (Patent Document 1), a leader cloth is disclosed having a structure of a fabric of a rectangular shape and a plurality of ropes, the ropes being fixed to the fabric by use of a plurality of grommets provided in the end portion thereof at uniform intervals. The ropes are bundled and hooked on a ring, and are pulled with another rope via the ring. In Translated National Publication of Patent Application No. 2003-502530 (Patent Document 2), a leader cloth is disclosed having a structure wherein three pieces of rectangular-shaped materials for forming a triangular shape are laminated In Translated National Publication of Patent Application No. 2003-514131(Patent Document 3), a leader cloth is disclosed having a substantially triangular shaped base material coated with polymer and reinforced with wires.
The leader cloth has a configuration as follows. In one end thereof, an apex portion is formed in the direction where the leader cloth is pulled onto the rolls in the paper machine, and a connecting member for connecting to a rope is provided in the apex portion of the leader cloth. The other end is the base portion having the same width as that of the belt, being connected to a new belt. The leader cloth is a wide cloth with a maximum width of over ten meters. Therefore, there is such a possibility that, while traveling, the leader cloth may generate sag and/or deflection causing a crease or fold when the leader cloth is pulled into the paper machine. In order to eliminate the deflection and to stabilize the leader cloth, ordinarily, in the end portion of the leader cloth, a steel pipe or an iron plate is attached in the width direction thereof as a stabilizer.
For example, in Japanese Patent Application Laid-Open No. Hei 8-284092 (Patent Document 4), a strip of cloth having the same width as that of a belt body 101, which is folded and covers the top and bottom face of a front-end portion of the belt body as shown in FIG. 2, is used as a leader cloth 102. The area closer to the turn edge 103 is stitched at a seam 104 and the loose edges thereof are flaps 106a and 106b. The belt body and the leader cloth are temporarily connected to each other with a temporary connecting portion (not shown). In a leader cloth having the structure as described above, a sack portion 105 is formed between the turn edge 103 and the seam 104. A core rod 107 of a wood, plastic or metal is inserted into the closed portion to reinforce the end portion of the leader cloth. The leader cloth attached with such a steel pipe is pulled onto the rolls via tow ropes 108.
[Patent Document 1] U.S. Pat. No. 5,306,393
[Patent Document 2] Translated National Publication of Patent Application No. 2003-502530
[Patent Document 3] Translated National Publication of Patent Application No. 2003-514131
[Patent Document 4] Japanese Patent Application Laid-Open No. Hei 8-284092